Heat exchanger and leak detection system

ABSTRACT

A system for heat exchange and leak detection is generally provided, the system including a heat exchanger including a first wall defining a first passage containing a first fluid. A leak detection enclosure containing a leak detection medium is defined between the first wall and a second wall surrounding the first wall.

FIELD

The present subject matter relates generally to heat exchangers and leakdetection systems for heat exchangers.

BACKGROUND

Heat exchanger systems often function using two or more working fluidsin thermal communication. However, the working fluids may need to befluidly segregated. Generally, the working fluids may be incompatible,volatile, or otherwise undesirable if mixed. Failure to segregate thefluids may substantially deteriorate or damage the heat exchanger systemor the system to which the heat exchanger is attached. As such, there isa need for a heat exchanger and leak detection system that may detectleakage or mitigate mixing of the working fluids.

BRIEF DESCRIPTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

One aspect of the present disclosure is directed to a system for heatexchange and leak detection. The system includes a heat exchangerincluding a first wall defining a first passage containing a firstfluid. A leak detection enclosure containing a leak detection medium isdefined between the first wall and a second wall surrounding the firstwall.

In one embodiment, the leak detection medium includes a fluid. The fluiddefines a pressure greater than the first fluid or a second fluidsurrounding the second wall.

In various embodiments, the system further includes a sensor disposed atthe leak detection enclosure. In one embodiment, the sensor defines anelectrical resistance sensor or an electrical conductivity sensor. Instill various embodiments, the sensor defines a pressure sensor. In oneembodiment, the sensor is coupled to a valve at the first passage. Thevalve defines a first position at or above a pressure threshold of theleak detection enclosure and a second position below the pressurethreshold of the leak detection enclosure. In another embodiment, thesensor is coupled to a valve at a second passage defined between a thirdwall and the second wall. The valve defines a first position at or abovea pressure threshold of the leak detection enclosure and a secondposition below the pressure threshold of the leak detection enclosure.In still another embodiment, the sensor defines a vibratory measurementsensor at the leak detection enclosure.

In one embodiment, the leak detection medium defines an electricalconductivity of approximately 3.50×10⁷ or greater.

In various embodiments, the leak detection medium defines a fluid. Inone embodiment, the system further includes a sensor disposed at one ormore of the first passage or a second passage. The sensor is configuredto detect the leak detection medium at the first fluid at the firstpassage or a second fluid at the second passage. In one embodiment, theleak detection medium includes an inert gas or liquid.

Another aspect of the present disclosure is directed to a heat exchangerand leak detection system. The system includes a first wall defining afirst passage containing a first fluid and a second wall surrounding thefirst wall. A leak detection medium is in a leak detection enclosuredefined between the first wall and the second wall. The system furtherincludes one or more controllers configured to perform operations. Theoperations include flowing the first fluid through the first passage;flowing a second fluid in thermal communication with the second wall;and acquiring, via a sensor at the leak detection enclosure, a signalindicating fluid communication between the leak detection medium and oneor more of the first fluid or the second fluid.

In various embodiments, the operations further include acquiring, viathe sensor, a first leak detection value at the leak detectionenclosure; acquiring, via the sensor, a second leak detection value atthe leak detection enclosure; determining, via the controller, a changein leak detection value at the leak detection enclosure based at leaston the acquired first leak detection value and the second leak detectionvalue; and determining, via the controller, a leakage at the leakdetection enclosure based at least on the acquired first leak detectionvalue and the second leak detection value.

In one embodiment, determining the change in leak detection value at theleak detection enclosure includes comparing the second leak detectionvalue to the first leak detection value over a period of time.

In another embodiment, the operations further include pressurizing theleak detection medium to a pressure at the leak detection enclosuregreater than a pressure at the first passage and the second passage.

In one embodiment of the system, the operations further includeacquiring, via a first passage sensor disposed at the first passage, afirst leak detection value at the first passage; acquiring, via a secondpassage sensor disposed at the second passage, a second leak detectionvalue at the second passage; acquiring, via the leak detection sensor, achange in leak detection value at the leak detection enclosure; anddetermining, via the controller, a leakage at one or more of the firstpassage, the second passage, and the leak detection enclosure based atleast on a difference between the first leak detection value and thesecond leak detection value each to the change in leak detection valueat the leak detection enclosure.

In another embodiment, acquiring a signal indicating leakage of the leakdetection medium into the first passage and/or the second passageincludes measuring a change in electrical resistance or electricalconductivity at the leak detection medium.

In still another embodiment, acquiring a signal indicating leakage ofthe leak detection medium into the first passage and/or the secondpassage includes measuring a change in vibratory measurement at the leakdetection medium.

In still yet another embodiment, the operations further includeadjusting an operating state of the heat exchanger based on the signalacquired from the sensor.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIGS. 1-7 are schematic cross-sectional views of exemplary embodimentsof a heat exchanger and leak detection system;

FIG. 8 is a schematic view of an exemplary embodiment of the systemshown and described in regard to FIGS. 1-7;

FIGS. 9-10 are cutaway perspective views of exemplary embodiments of aheat exchanger of the system according to FIGS. 1-8;

FIG. 11 is a flowchart outlining exemplary steps of a method for leakdetection at a heat exchanger system; and

FIG. 12 is an exemplary embodiment of a heat engine at which exemplaryembodiments of the system and methods shown and described in regard toFIGS. 1-11 may be disposed.

Repeat use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the present invention.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

As used herein, the terms “first”, “second”, and “third” may be usedinterchangeably to distinguish one component from another and are notintended to signify location or importance of the individual components.

The terms “upstream” and “downstream” refer to the relative directionwith respect to fluid flow in a fluid pathway. For example, “upstream”refers to the direction from which the fluid flows, and “downstream”refers to the direction to which the fluid flows.

Approximations recited herein may include margins based on one moremeasurement devices as used in the art, such as, but not limited to, apercentage of a full scale measurement range of a measurement device orsensor. Alternatively, approximations recited herein may include marginsof 10% of an upper limit value greater than the upper limit value or 10%of a lower limit value less than the lower limit value.

Embodiments of a heat exchanger and leak detection system, and methodsfor leak detection, that may detect leakage or mitigate mixing of theworking fluids are generally provided. The system generally includes aleak detection medium disposed between working fluids in a heatexchanger. Cracks, breakage, or other failures at one or more of a firstwall or a second wall enclosing the leak detection medium may mitigateleakage or fluid communication between the working fluids. The leakdetection medium may generally detect leakage of the working fluidsand/or failure of the first wall or second wall via one or more sensorsdetecting a change in pressure, electrical resistivity or conductivity,vibration or acoustics, or one or more other suitable measurementparameters.

Referring now to the drawings, FIG. 1 is a schematic view of anexemplary heat exchanger and leak detection system 90 (hereinafter,“system 90”) according to an aspect of the present disclosure. Thesystem 90 may be a portion of a heat engine or heat exchanger system forland-, air-, or sea-based systems or facilities. Such systems orfacilities may include, but are not limited to, liquid or gaseous heatexchangers including fuel, air, lubricant, hydraulic fluid, or gasworking fluids for aviation, aeronautic, or astronautic systems, powergeneration systems, nuclear systems, medical systems and scientificequipment measurement systems (e.g., magnetic resonance imaging,spectroscopy, cryogenics, etc.), or other heat exchanger safety criticalsystems.

Referring to FIG. 1, the system 90 includes a heat exchanger 100including a first wall 110 defining a first passage 105 containing afirst fluid 101. A leak detection enclosure 115 containing a leakdetection medium 103 is defined between the first wall 110 and a secondwall 120 surrounding the first wall 110. A second fluid 102 at leastpartially surrounds the second wall 120. The second fluid 102 is inthermal communication with the first fluid 101 through the leakdetection medium 103. The first fluid 101 and the second fluid 102 eachdefine working fluids enabling heat exchange to or from one another.

Referring now to FIG. 2, in various embodiments, the heat exchanger 100generally depicted in regard to FIG. 1 may further include a third wall130 surrounding the second wall 120. The third wall 130 and the secondwall 120 may together define a second passage 125 therebetween at leastpartially containing the second fluid 102. A member 135 may coupletogether the third wall 130 and the second wall 120. For example, themember 135 may define a substantially rectangular, circular, ovular,polygonal, etc. pillar or column extended between the third wall 130 andthe second wall 120. As another example, the member 135 may define awall extended at least partially circumferentially around the secondwall 120 (FIGS. 9-10). The member 135 may define the second passage 125as a plurality of chambers extended substantially circumferentiallyaround the second wall 120 (e.g., depicted in regard to FIG. 9-10). Themember 135 may extend substantially circumferentially around the secondwall 120 and further at least partially along a longitudinal directionsuch as to define a helical second passage 125 surrounding the secondwall 120 (FIG. 9-10).

Referring to FIGS. 1-2, during normal operation (i.e., not leaking) ofthe system 90, the first wall 110 encloses the first fluid 101 withinthe first passage 105 fluidly segregated from the leak detectionenclosure 115, the leak detection medium 103 therewithin, and/or thesecond fluid 102. Additionally, during normal operation, the first wall110 and the second wall 120 together enclose the leak detection medium103 within the leak detection enclosure 115 such as to be segregatedfrom the first fluid 101 and the second fluid 102. Still further, duringnormal operation, the second wall 120 segregates the second fluid 102from the leak detection medium 103 and the leak detection enclosure 115.

In various embodiments, the leak detection medium 103 defines a fluid.In one embodiment, the leak detection medium 103 defining the fluid isenclosed within the leak detection enclosure 115 at a pressure greaterthan the first fluid 101, the second fluid 102, or both. In anotherembodiment, the leak detection medium 103 defining the fluid is enabledto flow in a circuit at least partially defined by the leak detectionenclosure 115 at a pressure greater than the first fluid 101, the secondfluid 102, or both. As such, during adverse operation of the system 90,such as fluid communication between the first fluid 101 and the leakdetection medium 103 or fluid communication between the second fluid 102and the leak detection medium 103 (e.g., cracking, breakage, or otherfailure of the first wall 110 and/or the second wall 120) the leakdetection medium 103 may generally flow from the higher pressure leakdetection enclosure 115 into the first passage 105 or the second passage125.

Referring now to FIGS. 2-3, various embodiments of the system 90depicted in regard to FIGS. 1-2 further include a sensor 140 disposed atthe leak detection enclosure 115. The sensor 140 generally measures,calculates, gauges, or otherwise acquires and/or transmits a signal,shown graphically at 150, indicating fluid communication between theleak detection medium 103 and one or more of the first fluid 101 or thesecond fluid 102. The system 90 further determines whether there isleakage at the leak detection enclosure 115 (e.g., via leakage,breakage, damage, cracks, etc. at the first wall 110 or the second wall120) based at least on a change or difference in signals acquired fromthe sensor 140.

In one embodiment, the sensor 140 defines a pressure sensor. Forexample, the sensor 140 defining the pressure sensor generallydetermines, measures, calculates, gauges, or otherwise acquires and/ortransmits a pressure value of the leak detection medium 103 defining thefluid. The sensor 140 defining the pressure sensor acquires a pluralitypressure values at the leak detection enclosure 115.

In various embodiments, the sensor 140 defining the pressure sensoracquires a first pressure value and a second pressure value each at theleak detection enclosure 115. The system 90 determines a change inpressure or delta pressure at the leak detection enclosure 115 based atleast on the acquired first pressure value and the second pressurevalue. In one embodiment, acquiring the second pressure value is over aperiod of time from the acquired first pressure value. The secondpressure value and the first pressure value are compared versus theperiod of time to determine a change in pressure over the period oftime. For example, leakage at the first wall 110 and/or the second wall120 may be indicated via a decrease in pressure at the second pressurevalue over the period of time relative to the first pressure value. Asanother example, the leak detection medium 103 may generally becontained within the leak detection enclosure 115 as a substantiallystatic fluid. The sensor 140 may acquire static pressure values of theleak detection medium 103 in the leak detection enclosure 115 andcompare the change in pressure values over the period of time.

Referring now to FIGS. 4-5, in another embodiment of the system 90generally described in regard to FIGS. 1-3, acquiring the secondpressure value and the first pressure value is via a plurality ofsensors 140 disposed at an upstream end 99 and a downstream end 98 ofthe system 90. For example, the system 90 may include an upstream sensor141 disposed proximate to the upstream end 99 and a downstream sensor142 disposed proximate to the downstream end 98.

Referring to FIG. 4, the sensors 141, 142 may be disposed at the leakdetection enclosure 115 to acquire a delta pressure value of the leakdetection medium 103 defining a fluid flowing through the leak detectionenclosure 115. For example, the system 90 may acquire the secondpressure value via the downstream sensor 142 over a distance relative tothe first pressure value via the upstream sensor 141 such as todetermine a pressure loss across the distance between the sensors 141,142. The system 90 further acquires the second pressure value and thefirst pressure value over a period of time, such as continuous orintermittent acquisitions, or trending to determine whether the deltapressure between the second pressure value and the first pressure valueis changing over the period of time.

Referring to FIG. 5, the system 90 is configured substantially similarlyas shown and described in regard to FIGS. 1-4. In FIG. 5, the pluralityof sensors 140 are disposed at one or more of the first passage 105 orthe second passage 125. For example, the system 90 may include anupstream first passage sensor 143 and a downstream first passage sensor144 each disposed at the first passage 105. As another example, thesystem 90 may include an upstream second passage sensor 145 and adownstream second passage sensor 146 each disposed at the second passage125. The first passage sensors 143, 144 acquire a delta pressure valueof the first fluid 101 defining a fluid flowing through the firstpassage 105. The second passage sensors 145, 146 acquire a deltapressure value of the second fluid 102 defining a fluid flowing throughthe second passage 125. For example, the system 90 may acquire thesecond pressure value via the downstream sensor 144, 146 over a distancerelative to the first pressure value via the upstream sensor 143, 145such as to determine a pressure loss across the distance between therespective pairs of first passage sensors 143, 144 and the secondpassage sensors 145, 146. The system 90 further acquires the secondpressure value and the first pressure value over a period of time, suchas continuous or intermittent acquisitions, or trending to determinewhether the delta pressure between the second pressure value and thefirst pressure value is changing over the period of time.

In various embodiments, the sensors 140, 141, 142, 143, 144, 145, 146may be disposed at one or more of the first passage 105, the secondpassage 125, or the leak detection enclosure 115 via the member 135extended to the second wall 120. Referring to FIG. 5, in one embodiment,the member 135 may extend further to the first wall 110 such as todispose the sensor 140, 141, 142, 143 144, 145, 146 to the first passage105. The member 135 may generally enable egress of wires or othercommunication devices from the sensor 140 to a controller configured toreceive and/or transmit signals from the sensor 140 and executeoperations.

Referring now to FIGS. 1-5, in various embodiments, the leak detectionmedium 103 may define an electrical conductivity of approximately3.50×10⁷ or greater at approximately 20 degrees Celsius. For example,the leak detection medium 100 may define one or more materialsincluding, but not limited to, aluminum, gold, copper, silver, orcombinations thereof. It should be appreciated that the measure ofelectrical conductivity may be increase or decrease based on differenttemperatures. In one embodiment, the sensor 140 defines an electricalresistance sensor or an electrical conductivity sensor. For example,during normal operation of the system 90, the sensor 140 acquires asignal indicating a first electrical resistance or electricalconductivity of the leak detection medium 103. During adverse operationof the system 90, the sensor 140 acquires the signal indicating a secondelectrical resistance or electrical conductivity of the leak detectionmedium 103. The second electrical resistance or electrical conductivitymay generally indicate leakage of the first fluid 101 or the secondfluid 102 into the leak detection enclosure 115 such as to change theelectrical resistance or conductivity of the leak detection medium 103.

Referring still to FIGS. 1-5, in still various embodiments, the sensor140 may define a vibratory measurement sensor at the leak detectionenclosure 115. For example, the sensor 140 may define an accelerometeror an acoustic measurement device. During normal operation of the system90, the sensor 140 acquires a signal indicating a first vibratorymeasurement at the leak detection enclosure 115. During adverseoperation of the system 90, the sensor 140 acquires the signalindicating a second vibratory measurement at the leak detectionenclosure 115. The second vibratory measurement at the leak detectionenclosure 115 may generally indicate leakage of the leak detectionmedium 103 egressing from the leak detection enclosure 115 into one ormore of the first passage 105 or the second passage 125.

Additionally, or alternatively, the second vibratory measurement at theleak detection enclosure 115 may generally indicate leakage of the firstfluid 101 or the second fluid 102 into the leak detection enclosure 115.Still further, the sensor 140 may acquire the signal at the firstpassage 105, the second passage 125, or both to indicate a change invibratory measurement based on a leakage between the upstream end 99 andthe downstream end 98. For example, one or more of the upstream sensors141, 143, 145 may acquire a first vibratory measurement and one or moreof the downstream sensors 142, 144, 146 may acquire a second vibratorymeasurement, such as shown and described in regard to FIG. 5. The system90 may compare the second measurement and the first measurement todetermine whether there is a leakage at the leak detection enclosure.The system 90 may further compare the second measurement and the firstmeasurement to determine whether the leakage is at the first passage105, the second passage 125, or both.

Referring to FIG. 5, in one embodiment, the sensor 140 may be disposedat one or more of the first passage 105 or the second passage 125 toacquire a signal indicating leakage of the leak detection medium 103into the first passage 105 or the second passage 125. In one embodiment,the sensor 140 may define a gas detection sensor disposed at one or moreof the first passage 105 or the second passage 125 to indicate leakageof the leak detection medium 103 into the first passage 105 or thesecond passage 125. For example, the sensor 140 defining a gas detectormay more specifically define an electro-chemical gas detector. Thesensor 140 defining an electro-chemical gas detector may include achemically reactive semiconductor sensor. The chemically reactivesemiconductor may include a tin-oxide based sensor in which electricalresistance is altered due to the presence of the leak detection medium103 mixed with the first fluid 101 in the first passage 105 or thesecond fluid 102 in the second passage 125.

As another example, in one embodiment the sensor 140 defining a gasdetection sensor may further define one or more types of spectrometers.The sensor 140 defining a spectrometer may further define one or more ofa mass spectrometer, an optical spectrometer, an imaging spectrometer,or another spectrometer appropriate for detecting the leak detectionmedium 103 in the fluid 101, 102.

In various embodiments, the leak detection medium 103 may define a fluidsubstantially comprising an inert or noble gas, or liquefied form of thenoble gas. The inert or noble gas may include argon, helium, xenon,neon, krypton, radon, or oganesson, or combinations thereof. The sensor140 may define an inert or noble gas sensor such as to detect quantitiesof the leak detection medium 103 in the first passage 105 or the secondpassage 125, such as one or more aforementioned embodiments of thesensor 140.

Referring now to FIGS. 6-7, the system 90 shown and described in regardto FIGS. 1-5 may further include a valve 160 coupled to the sensor 140.The valve 160 defines a first position at or above a pressure thresholdof the leak detection enclosure 115. The valve 160 further defines asecond position below the pressure threshold at the leak detectionenclosure 115. In one embodiment, such as shown in regard to FIG. 6, thevalve 160 is disposed at the first passage 105. In another embodiment,such as shown in regard to FIG. 7, the valve 160 is disposed at thesecond passage 125. In other embodiments, the valve 160 may be disposedat the first passage 105 and the second passage 125. The valve 160receives a signal from the sensor 140 indicating the pressure value atthe leak detection enclosure 115. When the pressure value is greaterthan or equal to a predetermined pressure threshold, the valve 160defines the first position (e.g., an open position) such as to enableflow of the first fluid 101 through the first passage 105, or to enableflow of the second fluid 102 through the second passage 125, or both.When the pressure value is less than the predetermined pressurethreshold, the valve 160 defines the second position (e.g., a closedposition) such as to reduce or disable flow of the first fluid 101through the first passage 105, or flow of the second fluid 102 throughthe second passage 125, or both.

Referring now to FIGS. 1-7, the system 90 may further pressurize theleak detection enclosure 115. For example, the system 90 may pressurizethe leak detection enclosure 115 to or above the pressure threshold,such as to enable the system 90 to detect leakage of the leak detectionmedium 103 such as described in regard to FIGS. 1-7. The system 90 mayfurther pressurize the leak detection enclosure 115 to or above thepressure threshold such as to enable flow of the first fluid 101 and/orthe second fluid 102 such as described in regard to FIGS. 6-7. Invarious embodiments, the pressure threshold may define a predeterminedpressure value at the leak detection enclosure 115. In otherembodiments, the pressure threshold may define a predetermined pressuredifferential above the pressure value at the first passage 105 or thepressure value at the second passage 125. For example, the predeterminedpressure differential may be 1 megapascal (Mpa) or more (e.g., or 5 Mpa,or 10 Mpa, or 100 Mpa, etc.) greater than the greater of the pressurevalue at the first passage 105 or the pressure value at the secondpassage 125. As another example, the predetermined pressure differentialmay be a predetermined percentage greater than one or more of the firstpassage 105 or the second passage 125 (e.g., 1% greater, or 5% greater,or 10% greater, or 20% greater, etc.). In still various embodiments, thepredetermined pressure threshold may be based on a curve, chart,function, schedule, regression, or transfer function based on one ormore pressure values at the first passage 105, the second passage 125,or both.

Referring now to FIG. 8, a schematic view of the system 90 generallyshown and described in regard to FIGS. 1-7 is provided. It should beappreciated that although the schematic generally provided in regard toFIG. 8 includes features shown or described in regard to one or more ofthe embodiments shown and described in regard to FIGS. 1-7, the system90 may include arrangements or embodiments specific to one or several ofthe embodiments shown in regard to FIGS. 1-7.

The system 90 may further include one or more bypass conduits 111, 121enabling bypass of one or more of the fluids 101, 102 around all or partof the heat exchanger 100. The bypass conduit 111, 121 may enable bypassof one or more of the fluids 101, 102 based at least on the determinedleakage at the heat exchanger 100 such as described above. In oneembodiment, the fluid 101, 102 may bypass the heat exchanger 100 via thebypass conduits 111, 121 when the valve 160 defines the second positionsuch as described in regard to FIGS. 6-7. The first bypass conduit 111may enable bypass of the first fluid 101 from entering the first passage105 of the heat exchanger 100. The second bypass conduit 121 may enablebypass of the second fluid 102 from entering the second passage 125 ofthe heat exchanger 100. During adverse operation of the system 90, suchas indicating a leakage, the system 90 may reduce or disable flow of oneor more of the fluids 101, 102 into the heat exchanger 100 such as toreduce, mitigate, or eliminate undesired mixing of the fluids 101, 102due to leakage.

Embodiments shown and described in regard to FIGS. 1-8 may define apassive arrangement, such as the sensor 140 providing the signal to thevalve 160 and the valve 160 adjusting positions such as described above.Additionally, or alternatively, the system 90 may define an activearrangement further including a controller 210 such as depictedschematically in FIG. 8.

In general, the controller 210 can correspond to any suitableprocessor-based device, including one or more computing devices. Forinstance, FIG. 8 illustrates one embodiment of suitable components thatcan be included within the controller 210. As shown in FIG. 8, thecontroller 210 can include a processor 212 and associated memory 214configured to perform a variety of computer-implemented functions. Invarious embodiments, the controller 210 may be configured to operate thesystem 90 such as according to one or more steps of a method for leakdetection at a heat exchanger system (hereinafter, “method 1000”)generally described herein in regard to FIGS. 1-10 and outlined inregard to FIG. 11.

As used herein, the term “processor” refers not only to integratedcircuits referred to in the art as being included in a computer, butalso refers to a controller, microcontroller, a microcomputer, aprogrammable logic controller (PLC), an application specific integratedcircuit (ASIC), a Field Programmable Gate Array (FPGA), and otherprogrammable circuits. Additionally, the memory 214 can generallyinclude memory element(s) including, but not limited to, computerreadable medium (e.g., random access memory (RAM)), computer readablenon-volatile medium (e.g., flash memory), a compact disc-read onlymemory (CD-ROM), a magneto-optical disk (MOD), a digital versatile disc(DVD) and/or other suitable memory elements or combinations thereof. Invarious embodiments, the controller 210 may define one or more of a fullauthority digital engine controller (FADEC), a propeller control unit(PCU), an engine control unit (ECU), or an electronic engine control(EEC).

As shown, the controller 210 may include control logic 216 stored inmemory 214. The control logic 216 may include instructions that whenexecuted by the one or more processors 212 cause the one or moreprocessors 212 to perform operations such as described in regard tomethod 1000.

Additionally, as shown in FIG. 12, the controller 210 may also include acommunications interface module 230. In various embodiments, thecommunications interface module 230 can include associated electroniccircuitry that is used to send and receive data. As such, thecommunications interface module 230 of the controller 210 can be used toreceive data from the system 90 (e.g., the sensors 140, 141, 142, 143,144, 145, 146) providing pressure, flow, or temperature values,vibratory or acoustic measurements, electrical resistivity orconductivity measurements, or gas detection, or combinations thereof. Inaddition, the communications interface module 230 can also be used tocommunicate with any other suitable components of the system 90,including any number of valves 160 or bypass conduits 111, 121configured enable, disable, or alter flow of the fluids 101, 102, 103through the system 90.

It should be appreciated that the communications interface module 230can be any combination of suitable wired and/or wireless communicationsinterfaces and, thus, can be communicatively coupled to one or morecomponents of the system 90 via a wired and/or wireless connection. Assuch, the controller 210 may operate, modulate, or adjust operation ofthe system 90, acquire or transmit signals via the sensor 140, ordetermine leakage at the leak detection enclosure 115, or other stepssuch as described in regard to the method 1000.

Referring now to FIGS. 9-10, perspective cutaway views of exemplaryembodiments of the heat exchanger 100 of the system 90 are generallyprovided in accordance to one or more embodiments shown and described inregard to FIGS. 1-8. All or part of the system 90 including the heatexchanger 100 may be part of a single, unitary component and may bemanufactured from any number of processes. These manufacturing processesinclude, but are not limited to, those referred to as “additivemanufacturing” or “3D printing”. Additionally, any number of casting,machining, welding, brazing, or sintering processes, or any combinationthereof, may be utilized to construct the heat exchanger 100, including,but not limited to, the first wall 110, the second wall 120, the thirdwall 130, the member 135, passages, cavities, openings, or egresses forthe sensor 140 and/or valve 160, or combinations thereof. Furthermore,the system 90 may constitute one or more individual components that aremechanically joined (e.g. via bolts, nuts, rivets, or screws, or weldingor brazing processes, or combinations thereof) or are positioned inspace to achieve a substantially similar geometric, aerodynamic, orthermodynamic results as if manufactured or assembled as one or morecomponents. Non-limiting examples of suitable materials includehigh-strength steels, titanium and titanium-based alloys, nickel andcobalt-based alloys, aluminum, and/or metal, polymer, or ceramic matrixcomposites, or combinations thereof.

Referring to FIGS. 1-10, in various embodiments, one or more of thefluids 101, 102, 103 define a liquid or gaseous fuel, compressed air,refrigerant, liquid metal, inert gas, a supercritical fluid, compressedair, or combinations thereof. Various embodiments of the fluids 101,102, 103 defining a supercritical fluid may include, but is not limitedto, carbon dioxide, water, methane, ethane, propane, ethylene,propylene, methanol, ethanol, acetone, or nitrous oxide, or combinationsthereof.

In still various embodiments, the fluids 101, 102, 103 defining arefrigerant may include, but is not limited to, halon, perchloroolefin,perchlorocarbon, perfluoroolefin, perfluororcarbon, hydroolefin,hydrocarbon, hydrochloroolefin, hydrochlorocarb on, hydrofluoroolefin,hydrofluorocarbon, hydrochloroolefin, hydrochlorofluorocarbon,chlorofluoroolefin, or chlorofluorocarbon type refrigerants, orcombinations thereof.

Still further various embodiments of fluids 101, 102, 103 defining arefrigerant may include methylamine, ethylamine, hydrogen, helium,ammonia, water, neon, nitrogen, air, oxygen, argon, sulfur dioxide,carbon dioxide, nitrous oxide, or krypton, or combinations thereof.

Various embodiments of the system 90 may adjust an operating state ofthe heat exchanger 100 based on the signal acquired from the sensor 140.Adjusting the operating state of the system 90 may include adjusting apressure, flow rate, and/or temperature of fluid 101, 102 at the heatexchanger 100. Additionally, or alternatively, adjusting the operatingstate of the system 90 may include bypassing one or more of the fluids101, 102 via one or more of the bypass conduits 111, 121. Furthermore,or alternatively, adjusting the operating state of the system 90 mayinclude adjusting or modulating the valve 160 to adjust the pressure,flow rate, and/or temperature of one or more of the fluids 101, 102 atthe heat exchanger 100.

Referring now to FIG. 11, a flowchart outlining exemplary steps of amethod for leak detection at a heat exchanger system is generallyprovided (hereinafter, “method 1000”). Although generally shown anddescribed in regard to FIGS. 1-10, the method 1000 may be performed orutilized in other structures or systems not generally provided herein.Additionally, although the steps outlined herein are presented in aparticular order, the steps may be rearranged, reordered, omitted,added, or otherwise altered without deviating from the scope of thepresent disclosure.

The method 1000 may include at 1010 flowing the first fluid through thefirst passage; at 1020 flowing a second fluid in thermal communicationwith the second wall; and at 1030 acquiring a signal indicating fluidcommunication between the leak detection medium and one or more of thefirst fluid or the second fluid, such as shown and described in regardto the system 90 in FIGS. 1-10.

In various embodiments, the method 1000 may further include at 1040acquiring a first leak detection value at the leak detection enclosure;at 1050 acquiring a second leak detection value at the leak detectionenclosure; and at 1060 determining a change in leak detection values atthe leak detection enclosure based at least on the acquired first leakdetection value and the second leak detection value.

In still various embodiments, the leak detection value may be acquiredvia a sensor (e.g., sensor 140, 141, 142, 143, 144, 145, 146) at step1030. The sensor may acquire leak detection values indicating a pressurevalue, an electrical resistivity or conductivity, a vibratory oracoustic measurement. In one embodiment at 1030, acquiring a signalindicating leakage of the leak detection medium into the first passageand/or the second passage includes measuring a change in electricalresistance or electrical conductivity at the leak detection medium. Inanother embodiment at 1030, acquiring a signal indicating leakage of theleak detection medium into the first passage and/or the second passageincludes measuring a change in vibratory measurement at the leakdetection enclosure, the first passage, or the second passage.

In one embodiment at 1060, determining a change in leak detection valuesat the leak detection enclosure includes comparing the second leakdetection value to the first leak detection value over a period of time.In various examples, such as described in regard to FIGS. 1-10,comparing the leak detection values may include comparing staticpressure measurements at the leak detection enclosure over a period oftime to determine a change (e.g., decrease) indicating leakage of theleak detection medium into the first passage, the second passage, orboth. As another example, comparing the leak detection values mayinclude comparing a change in difference between a downstream leakdetection value and an upstream leak detection value over a period oftime. In still another example, comparing the leak detection values mayinclude comparing a change in presence of the leak detection medium inthe first fluid or the second fluid (e.g. a change indicating presenceof the leak detection medium defining an inert gas in the first fluid orsecond fluid). In still various examples, comparing leak detectionvalues includes comparing changes in vibratory measurements, pressures,or electrical resistance or conductance.

In various embodiments, the method 1000 further includes at 1071acquiring a first leak detection value change at the first passage; at1072 acquiring a second leak detection value change at the secondpassage; at 1073 acquiring a change in leak detection medium values atthe leak detection enclosure; and at 1074 determining a leakage at oneor more of the first passage, the second passage, and the leak detectionenclosure based at least on a difference between the first leakdetection value change and the second leak detection value change eachto the change in leak detection medium values at the leak detectionenclosure.

In yet another embodiment, the method 1000 may further include at 1080adjusting an operating state of the heat exchanger (e.g., heat exchanger100) based on the signal acquired from the sensor. In variousembodiments, adjusting the operating state may include adjusting, viathe valve (e.g., valve 160), a pressure, flow rate, and/or temperatureof the fluid (e.g., fluid 101, 102) entering and/or egressing the heatexchanger 100. In another embodiment, adjusting the operating state ofthe heat exchanger includes bypassing, at least in part, one or more ofthe first fluid or the second fluid from the first passage or secondpassage. For example, the method 1000 at 1080 may be exemplified such asshown and described in regard to FIG. 8 (e.g., the bypass conduits 111,121).

The method 1000 may further include at 1090 determining a leakage at theleak detection enclosure based at least on the acquired first leakdetection value and the second leak detection value. For example, themethod 1000 at 1090 may be exemplified such as shown and described inregard to FIGS. 1-10.

The method 1000 may further include at 1005 pressurizing the leakdetection medium to a pressure at the leak detection enclosure greaterthan a pressure at the first passage and the second passage. Forexample, the method 1000 at 1005 may be exemplified such as shown anddescribed in regard to FIGS. 1-10.

Referring now to FIG. 12, a schematic partially cross-sectioned sideview of an exemplary heat engine 10 (herein referred to as “engine 10”)as may incorporate various embodiments of system 90 is generallyprovided. It should be appreciated that FIG. 12 is provided by way ofexample and that in various embodiments the system 90 may beincorporated into power generation systems, nuclear systems, medicalsystems and scientific equipment measurement systems (e.g., magneticresonance imaging, spectroscopy, cryogenics, etc.), or other heatexchanger safety critical systems.

Although further described herein as a gas turbine engine, the engine 10may define a steam turbine engine, or a turbo machine generally,including turbofan, turbojet, turboprop, or turboshaft gas turbineengine configurations, or combined cycle engines. As shown in FIG. 12,the engine 10 has a longitudinal or axial centerline axis 12 thatextends therethrough for reference purposes. In general, the engine 10may include a fan assembly 14 and a core engine 16 disposed downstreamof the fan assembly 14.

The core engine 16 may generally include a substantially tubular outercasing 18 that defines an annular inlet 20 into a core flowpath 19defined through the core engine 16. The outer casing 18 encases or atleast partially forms, in serial flow relationship, a compressor section21, such as having a booster or low pressure (LP) compressor 22 and ahigh pressure (HP) compressor 24; a combustion section 26; and anexpansion section or turbine section 31, such as including a highpressure (HP) turbine 28 and a low pressure (LP) turbine 30. The turbineor expansion section 31 further includes a jet exhaust nozzle section 37through which combustion gases 86 egress from the core engine 16. Invarious embodiments, the jet exhaust nozzle section 37 may furtherdefine an afterburner. The core engine 16 further defines a hot section33 comprising the combustion section 26, the turbine or expansionsection 31, and the jet exhaust nozzle section 37, through whichcombustion gases 86 are formed and flow. A high pressure (HP) rotorshaft 34 drivingly connects the HP turbine 28 to the HP compressor 24. Alow pressure (LP) rotor shaft 36 drivingly connects the LP turbine 30 tothe LP compressor 22. The LP rotor shaft 36 may also be connected to afan shaft 38 of the fan assembly 14. In particular embodiments, as shownin FIG. 1, the LP rotor shaft 36 may be connected to the fan shaft 38via a reduction gear 40 such as in an indirect-drive or geared-driveconfiguration.

As shown in FIG. 12, the fan assembly 14 includes a plurality of fanblades 42 that are coupled to and that extend radially outwardly fromthe fan shaft 38. An annular fan casing or nacelle 44 circumferentiallysurrounds the fan assembly 14 and/or at least a portion of the coreengine 16. It should be appreciated by those of ordinary skill in theart that the nacelle 44 may be configured to be supported relative tothe core engine 16 by a plurality of circumferentially-spaced outletguide vanes or struts 46. Moreover, at least a portion of the nacelle 44may extend over an outer portion of the outer casing 18 of the coreengine 16 so as to define a fan bypass airflow passage 48 therebetween.

During operation of the engine 10, a volume of air as indicatedschematically by arrows 74 enters the engine 10 through an associatedinlet 76 of the fan case or nacelle 44 and/or fan assembly 14. As theair 74 passes across the fan blades 42 a portion of the air, asindicated schematically by arrows 78, is directed or routed into thebypass airflow passage 48 while another portion of the air as indicatedschematically by arrow 80 is directed or routed into the core flowpath19 of the core engine 16 at the LP compressor 22. Air 80 isprogressively compressed as it flows through the core flowpath 19 acrossthe LP and HP compressors 22, 24 towards the combustion section 26, suchas shown schematically by arrows 81 depicting an increasing pressure andtemperature of the flow of compressed air and arrows 82 depicting anexit temperature and pressure from the compressor section 21 (e.g.,defining an inlet temperature and pressure to the combustion section26). The now compressed air 82 flows into the combustion section 26 tomix with a liquid or gaseous fuel and burned to produce combustion gases86. The combustion gases 86 generated in the combustion section 26 flowdownstream through the core flowpath 19 into the HP turbine 28, thuscausing the HP rotor shaft 34 to rotate, thereby supporting operation ofthe HP compressor 24. The combustion gases 86 are then routed throughcore flowpath 19 across the LP turbine 30, thus causing the LP rotorshaft 36 to rotate, thereby supporting operation of the LP compressor 22and/or rotation of the fan shaft 38 and fan blades 42. The combustiongases 86 are then exhausted through the jet exhaust nozzle section 37 ofthe core engine 16 to provide propulsive thrust.

In the embodiment generally provided in FIG. 12, the engine 10 furtherdefines a third stream bypass airflow passage 49. The third streambypass airflow passage 49 is defined at least partially through theouter casing 18 from a compressor of the compressor section 21 (e.g.,the LP compressor 22) to the fan bypass airflow passage 48. The thirdstream bypass airflow passage 49 selectively allows a flow of thecompressed air 80, 81, shown schematically by arrows 79, from acompressor of the compressor section 21 (e.g., from the LP compressor22) to mix with the portion of air 78 in the fan bypass airflow passage48. The engine 10 enables the third stream bypass airflow passage 49 tocompletely or substantially close the flow of compressed air 79 fromegressing to the fan bypass airflow passage 48 based on an operatingcondition of the engine 10 (e.g., high power conditions), such as toincrease thrust output of the engine 10. The engine 10 further enablesthe third stream bypass airflow passage 49 to at least partially openthe flow of compressed air 79 to egress to the fan bypass airflowpassage 48 based on an operating condition of the engine 10 (e.g., lowor mid power conditions), such as to reduce fuel consumption.

It should be appreciated that although the exemplary embodiment of theengine 10 generally provided in FIG. 12 is presented as a three-streamturbofan configuration, the engine 10 may define a two-stream (e.g., fanbypass airflow passage 48 and core flowpath 19) or one-stream heatengine configuration (e.g., core flowpath 19). It should further beappreciated that although the exemplary embodiment of the engine 10generally provided in FIG. 1 is presented as a two-spool turbofanconfiguration, the engine 10 may define a third or more spoolconfiguration in which the LP compressor 22 defines an intermediatepressure (IP) compressor coupled to an IP shaft and IP turbine, eachdisposed in serial flow relationship between a respective fan assembly14, HP compressor 24, HP turbine 28, and LP turbine 30. Still further,the three-spool configuration may further couple the fan assembly 14 tothe LP turbine 30 mechanically independent from the LP/IP compressor 22and an IP turbine. Stated alternatively, the engine 10 may define threemechanically independent spools including respective combinations of afan assembly and LP turbine, an IP compressor and IP turbine, and an HPcompressor and HP turbine.

Referring now to FIGS. 1-12, in various embodiments, one or more of thefluids 101, 102, 103 may define a liquid or gaseous fuel at the engine10. The fuels may include, but are not limited to, gasoline or petrol,propane, ethane, hydrogen, diesel, kerosene or one or more jet fuelformulations (e.g., Jet A, JP1, etc.), coke oven gas, natural gas, orsynthesis gas, or combinations thereof. The fluid 101, 102, 103 definingoxidizer generally or air may include the flow of bypass air 78, 79 fromthe fan assembly 14 or compressor section 21 bypassing the combustionsection 26, such as described in regard to FIG. 12 and flows through thefan bypass airflow passage 48 and/or the third stream bypass airflowpassage 49.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A system for heat exchange and leak detection,the system comprising: a heat exchanger defining a radial direction andcomprising: a first wall defining a first passage containing a firstfluid, a second wall surrounding the first wall, and a third wallsurrounding the second wall, wherein the first fluid is a working fluidfor the heat exchanger, wherein a leak detection enclosure containing aleak detection medium is defined between the first wall and the secondwall, wherein a second passage is defined between the second wall andthe third wall, wherein the second passage contains a second fluid,wherein the first passage has a larger thickness in the radial directionthan the leak detection enclosure, wherein one of the first fluid andthe second fluid is compressed air, and the other of the first fluid andthe second fluid is a refrigerant, and wherein the leak detection mediumis an inert gas.
 2. The system of claim 1, wherein the leak detectionmedium comprises a fluid, and wherein the fluid has a pressure greaterthan the first fluid or the second fluid.
 3. The system of claim 1,further comprising: a sensor disposed at the leak detection enclosure.4. The system of claim 3, wherein the sensor defines a vibratorymeasurement sensor at the leak detection enclosure.
 5. The system ofclaim 3, wherein the sensor defines an electrical resistance sensor oran electrical conductivity sensor.
 6. The system of claim 3, wherein thesensor defines a pressure sensor.
 7. The system of claim 6, wherein thesensor is coupled to a valve within the first passage, wherein the valvedefines a first position at or above a pressure threshold of the leakdetection enclosure and a second position below the pressure thresholdof the leak detection enclosure.
 8. The system of claim 6, wherein thesensor is coupled to a valve at a within the second passage, wherein thevalve defines a first position at or above a pressure threshold of theleak detection enclosure and a second position below the pressurethreshold of the leak detection enclosure.
 9. The system of claim 1,wherein the leak detection medium defines an electrical conductivity ofapproximately 3.50×107 or greater.
 10. The system of claim 1, furthercomprising: a sensor disposed at one or more of the first passage or thesecond passage, wherein the sensor is configured to detect the leakdetection medium at the first fluid at the first passage or the secondfluid at the second passage.
 11. The system of claim 1, wherein the heatexchanger is configured to flow a first portion of the second fluidthrough the second passage in a parallel flow direction with respect tothe first fluid through the first passage, and wherein the heatexchanger is configured to flow a second portion of the second fluidthrough the second passage in a counter flow direction with respect tothe first fluid through the first passage.
 12. A heat exchanger and leakdetection system, the system comprising a heat exchanger defining aradial direction and comprising: a first wall defining a first passagecontaining a first fluid, a second wall surrounding the first wall, athird wall surrounding the second wall, and one or more controllersconfigured to perform operations, wherein a leak detection medium is ina leak detection enclosure defined between the first wall and the secondwall, wherein first fluid is a working fluid for the heat exchanger,wherein a second passage is defined between the second wall and thethird wall, wherein the second passage contains a second fluid, whereinthe first passage has a larger thickness in the radial direction thanthe leak detection enclosure, wherein one of the first fluid and thesecond fluid is compressed air, and the other of the first fluid and thesecond fluid is a refrigerant, and wherein the leak detection medium isan inert gas, the operations comprising: flowing the first fluid throughthe first passage; flowing the second fluid in thermal communicationwith the second wall; and acquiring, via a sensor at the leak detectionenclosure, a signal indicating fluid communication between the leakdetection medium and one or more of the first fluid or the second fluid.13. The system of claim 12, the operations further comprising:acquiring, via the sensor, a first leak detection value at the leakdetection enclosure; acquiring, via the sensor, a second leak detectionvalue at the leak detection enclosure; determining, via the controller,a change in leak detection value at the leak detection enclosure basedat least on the acquired first leak detection value and the second leakdetection value; and determining, via the controller, a leakage at theleak detection enclosure based at least on the acquired first leakdetection value and the second leak detection value.
 14. The system ofclaim 13, wherein determining the change in leak detection value at theleak detection enclosure comprises comparing the second leak detectionvalue to the first leak detection value over a period of time.
 15. Thesystem of claim 13, the operations further comprising: pressurizing theleak detection medium to a pressure at the leak detection enclosuregreater than a pressure at the first passage and the second passage. 16.The system of claim 12, the operations further comprising: acquiring,via a first passage sensor disposed at the first passage, a first leakdetection value at the first passage; acquiring, via a second passagesensor disposed at the second passage, a second leak detection value atthe second passage; acquiring, via the leak detection sensor, a changein leak detection value at the leak detection enclosure; anddetermining, via the controller, a leakage at one or more of the firstpassage, the second passage, and the leak detection enclosure based atleast on a difference between the first leak detection value and thesecond leak detection value each to the change in leak detection valueat the leak detection enclosure.
 17. The system of claim 12, whereinacquiring a signal indicating leakage of the leak detection medium intothe first passage and/or the second passage includes measuring a changein electrical resistance or electrical conductivity at the leakdetection medium.
 18. The system of claim 12, wherein acquiring a signalindicating leakage of the leak detection medium into the first passageand/or the second passage includes measuring a change in vibratorymeasurement at the leak detection medium.
 19. The system of claim 12,the operations further comprising: adjusting an operating state of theheat exchanger based on the signal acquired from the sensor.
 20. Themethod of claim 12, further comprising: flowing a first portion of thesecond fluid through the second passage in a parallel flow directionwith respect to the first fluid through the first passage, and flowing asecond portion of the second fluid through the second passage in acounter flow direction with respect to the first fluid through the firstpassage.